Saab 9-3 airbag system - detailed description WIS, programy
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8. Body\Airbag system
Technical description - Detailed ...
4D, 5D
CV
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 8. Body\Airbag system
Technical description - Detailed ...
ACM (Airbag Control Module)
The control module has the capacity to activate 16 detonation circuits and contains two
integrated accelerometers. The primary (1) accelerometer measures acceleration and
deceleration forces longitudinally and laterally. The secondary (2) accelerometer measures
longitudinal acceleration forces only.
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8. Body\Airbag system
Technical description - Detailed ...
CV: The control module has a roll-over function which means it can measure angle changes.
Angle changes are registered through an extra sensor in the control module.
Four side impact sensors send information to the control module regarding side impact
intensity and diagnostics. The side impact sensors deploy a side airbag and an inflatable
curtain on the side registering an impact.
Conditions
The system can be activated at several levels based on the impact force, seat position and use
of belts. It is activated individually for the driver and passengers, which means that different
decisions can be made for action depending on the seat position and whether or not the belt is
in use.
The front airbags are activated in step 1 or step 2 under different impact forces.
Step 1 means a low force impact and step 2 a high force impact. The front airbag is activated
earlier if the seatbelt is not fastened.
CV: The roll-over function measures the angular velocity with a gyro and is dependent on the
vehicle speed.
Front collision:
At low force impact, the belt tensioners are used. One condition for activation of the driver
and front-seat passenger belt tensioners is that the belt is in use.
If the impact force is greater, the front airbags are also activated in step 1 or step 2.
Step 1:
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  8. Body\Airbag system
Technical description - Detailed ...
At this level, the battery disconnect switch and the first of the two stages of the front airbags
are also activated, which means that around 70% of the maximum pressure is attained.
Step 2:
4D, 5D: At high impact force, the inflatable curtains and the second stage of the front airbag
are activated. CV: At high impact force, the roll bars and the second stage of the front airbag
are activated
Stage two is activated after a 5 to 20 ms delay after stage one in order to maximise
protection. Activation of stage two presumes that stage one (70% of max. pressure) and the
charge for stage two (during which the remaining 30% of the max. pressure is used) have
been triggered. Stage two is only triggered if the seat is more than 30% from its frontmost
position. This applies driver's seats in all markets as well as passenger seats in some markets.
In situations where the front airbags are only activated in stage 1, there will be a safety
activation of stage 2 after 100 ms for the passenger and 50 ms for the driver irrespective of
seat position. This is done to disarm the airbag and ensure there is no charge left after the
crash.
Side impact
4D, 5D: In the event of a side impact, only the side airbag and inflatable curtain on the side
of the impact will inflate but all belt pretensioners are activated. A precondition for the driver
and passenger belt pretensioner being activated is that the belt is being used.
CV: In the event of a side collision the appropriate side airbag is activated and both roll bars
are raised. The side air bag protects both the head and the torso. All the belt pretensioners
are activated. A precondition for the driver and passenger belt pretensioner to be activated is
that the belt is buckled up.
Backup power
The control module is equipped with a built-in backup power source which provides voltage for
150 ms after the normal power supply has been disconnected. The function has three
capacitors which maintain system current and allow for front airbag deployment during the
150 ms interval. The side impact sensors are disabled in order to save energy. During the
time interval, bus communication occurs continuously.
Driver airbag
There is a gas generator and a nylon fabric bag on the driver side. The gas generator is bolted
in a thermosetting plastic housing. The airbag is protected by a plastic casing with notches
that is fitted to the plastic housing. The airbag has a volume of about 60 litres.
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 8. Body\Airbag system
Technical description - Detailed ...
The airbag is of a two stage type. This means that it can be activated in two stages with
different pressures depending on the force of impact and the position of the seat. The airbag
consists of a thermosetting plastic housing, two electric detonators with different codings and
two pyrotechnical charges with different amounts of powder for stages 1 and 2 as well as a
filter.
Driver airbag gas generator
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